Piston



Nov. 6, 1934. 1 FREEDMAN 1,979,967

PISTON Filed NOV. 19, 1932 2 Sheets-Sheet l Patented Nov. 6v, 1934 UNHTEPAENT claims. (C1. 3094.41)

This invention relates generally to pistons and locomotive pistonembodying the present invenparticularly to expanding devices for thepiston tion.

rings oi locomotives and other steam engines. Figure 6 is a part end andpart sectional view In United States Patent No. 1,733,957, isof aportion oi the piston appearing in Figure 5. 5j sued October 29, 1929,there is described an ap- Figure 'l is a sectional View substantiallyalong 60 paratus for expanding the piston rings of Iocothe line 7 7 ofFigure 5. This view also shows motives and other steam engines and theprina portion oi the front cylinder head which is ciples of theexpanding device described. In the slightly modied to suit the improvedpiston particular embodiment of the piston ring exconstruction.

; pander shown and described in that patent, In accordance with thepresent invention, 65 some diii'iculty is encountered in installing thegenerally stated. anexpanding device for piston expander in pistonswhich are already made and rines may be installed in 01d 0r used pistonheads in service.v The particular embodiment illusin a convenient mannerby providing the optrated in that patent. is adapted particularly forerating. parts of the expander in a suitable cas- 15.- installation. inany piston or pistons in which ing having an internal opening of a shapesuit- 70 the expander receiving recesses are cast origiable for guidingthe parts and preferably being nally With the .piston head. cylindricalon the exterior. Such an assembly The present invention is in the natureof anmay be readily inserted and conveniently reother embodiment of theapparatus shown and tained in a bore hole which is drilled in thedescribed in the above. mentioned patent and is usual manner. The casingin which the operat- 75 particularly adapted for installation in oldpising parts of the expander are assembled may tons. be provided with asuitable closure accessible An object of this invention, generallystated, when the head of the cylinder of the engine is is to provide apiston ring expander which may remOVed S0 as t0 permit adjustment 0f theparts V be readily installed in pistons. Within the casing; 80

Another object of this invention is to provide In Figures l and 2 theinvention is shown ema piston ring assembly adapted for installationbodied in a box type piston presenting spaced in a cylindrical bore holewhich may be formed end Walls 5 and 6 and a solid peripheral porinapiston. tion 7, the latter having the usual ring receivf3()` AA furtherobject of. this invention is to proing grooves 8` in which theexpansible packing 85 vide a ring expanding assembly suitable for userings 9 are fitted.

in socalled two piece pistons. According to the present invention, aplurality A more specific object of this invention is to` of axiallyextending casings 10 are mounted in provide a piston ring lexpandingdevice assemthe piston Walls 5 and 6 and serve as housings 35.v bledwithin ar cylindrical casing which is adapted for the spring devices ofthe ring eXp-andina 90 to be installed in a cylindrical bore hole orremeans hereinafter deSCrbed. Each Casing has cess formed in the body orhead of the piston. an externally l'fhleaded end engaged in a thread-Other objects will. become apparent to those ed opnmg 11 formed 1n thepton Wall 5 the skilled in the art when the following descriptionOPPOSI@ end 0f the @esule beme tted in a .40, .n mecton with the accoman in recess 12V in the piston Wall 6. In the embodi- 95 ralvgslincgvhch p y g ment illustrated the bore of each casing is open Figure 1is an end view partly in section of at both ends and may be Shaped topresent a cylindrical portion 13 and a rectangular por- 011@ form 0flocomotlve plston embodymg the tion 14. The cylindrical portion 13 islocated plesjent l'lVfmtOnat the externally threaded end of the casing100 K Figure 1s a partial sectional view on the line and: is tapped toreceive a threaded Closure plugv 2-2 of Figure l. 13a Which is. securedagainst accidental loosen- Figure 3 is a longitudinal section through aing by means of a split retaining ring 15 tted housing containing aspring device constructed iny an annular groove 16. The rectangular popand assembled in accordance with this invention 14 of the casing boreextends from the 105 tion. cylindrical portion 13 to the opposite end ofthe Figure 4 S a rOIlt end View 0f the housing as casing Where it isclosed by the bottom Wall of it appears when the closure plug and springdethe recess 12. vice appearing in Figure 3 are removed. Mountedin eachof the casings 10 and ar- Figure 5 is an. end view oi a different typeoi ranged for movement up and down within the 110 rectangular recess 14may be a suitable resilient expanding device which may compriseoppositely bowed leai springs 17 and 18 having their center portionsfastened together as by a rivet 19. The lower spring 18 may rest upon aplate 20 having upturned ends 21 providing shoulders between which thespring 18 may be retained. In the embodiment illustrated, plate 20preferably corresponds in width to the width of rectangular opening 14of the casing 10, but with suicient looseness to permit the same to bemoved up and down therein in a direction laterally of the piston asshown in Figure 1. The upper spring 17 may be similarly retained betweendownturned end portions 23 of an abutment plate 22 which, like plate 20,substantially corresponds in width to the width of the opening 14, butis movable up and down therein. Bearing upon the upper surface oftheplate 22 is a series of thrust members 24 which project into the casing10 through suitable openings 25. These thrust members, 24 extend throughsuitable bores `26 which connect the piston ring grooves 8 with therecesses in which the casing 10 is mounted. Thrust member 24 may befitted with some looseness in the bores 26 so as to permit the passageof steam thereby in order that the external pressure of the respectivepiston rings 9 may be acquired from the interior. Atl their outer endsthrust members 24 may be provided with pressure plates 27 fitted betweenthe bottoms of grooves 8 and packing rings 9. It is apparent that whenthe parts are assembled in the positions shown in Figures 1 and 2 thepressure of springs 17 and 18 is effective to bias thrust members 24radially outwardly and thus to expand piston rings 9 against the wallsof the cylinder.

When it is desired to take up wear on the packing rings 9, this may beconveniently accomplished by removing the closure plugs 13a. of thecasing 10 and inserting one or more shirns (not shown) between thebottom portions of the casing and the spring supporting plates 20.

With a plurality of such piston ring expanding assemblies mounted inperipherally spaced relation about the head of a piston, it is apparentthat the piston rings may be readily and uniformlyexpanded not only tocompensate for wear, but also to more evenly distribute the weight ofthe piston head and thereby to leliminate, to a great extent, excessivewear on the lower side of the piston rings. It is apparent that thedevice operating through suitable springs maintains a uniform pressureon each of the piston rings, so that the same is maintained in closecontact with the interior ofthe cylinder. It will be apparent thatadjustment of the expanding devices to expand rings 9 in order to takeup wear may be accomplished without removing the piston from thecylinder, since by removal of the head of the cylinder, plugs 13a areaccessible and may be removed to permit shimming up of the expandingdevice.

Under some circumstances, it is desirable to provide additional meansfor preventing possible disassociation of the bowed springs 17 and 18and abutment plates 20 and 22. A convenient form of such means isillustrated in Figure 3 and may comprise a horizontal portion 58 adaptedto extend beneath lower plate y20 and having at each end thereofupwardly extending parts 59 which extend for substantially the fullheight of the rectangular opening 14. Upstanding parts 59 may have theirrespective ends turned inwardly as shown at so as to substantiallyenclose the spring expanding device. With such an arrangement, it isapparent that the upper plate 22 may be held against displacementrelative to the other members of the assembly when the piston is removedfrom the cylinder.

In the embodiment shown in Figures 5 to 7 inclusive, the ring expandingassembly is shown as applied to a two piece piston, having a piston head28 of the bull ring type. As shown, the piston head 28 may be providedwith a iiange 29 adapted to be secured to body 31 as shown by rivet 30.In accordance with this invention the casing for the piston ringexpander assembly may take the form of a bolt 32 which may supplant oneor more rivets 30. On the interior of the bolt 32, the adjustableexpanding arrangement hereinbefore described may be mounted. It will beunderstood, of course, that the bolt 32 corresponds in function to thecasing 10 hereinbefore described and differs from the casing 10 in thatit is provided at one end with a shoulder 33 which operates as the headof the bolt and at the other end is threaded as at 34 to receive a nut35.

Pistons of the type illustrated in Figures 5, 6 and 7 are often operatedin cylinders, the heads of which are generally convex in shape asillustrated in Figure '7. In order to provide sufficient clearancebetween the end of bolt 32 and the cylinder head 38 when the piston isat the limit of its travel nearest the head 38 a hole may be drilledthrough the head 38, threaded and provided with a plug 39, as shown inFigure 1. The inner surface of plug 39 may have a cavity 40 into whichthe front end of the bolt 32 may extend. It will be understood, ofcourse, that one such plug 39 is provided for each of the expanderassemblies which are mounted in casings of the type of bolt 32 when theconditions demand.

From the foregoing description it will be understood that the piston ofthe present invention is not limited to the specic details ofconstruction which have been hereinbefore, for the purpose ofillustration, referredv to. Furthermore, it is apparent that manymodications of the apparatus will present themselves to those skilled inthe art which will not depart from the spirit of this inventionand it isto be distinctly understood, therefore, that such modications and theuse of such individual features and sub-combinations of features as donot depart from the spirit of this invention are, although notspecically described herein, contemplated by and within the scope of theappended claims.

Having thus described the invention, what is claimed is:

1. In a piston of the character described having a body and anexpansible packing ring mounted therein, a casing removably mounted inthe body, an expanding device in said casing, and a thrust memberextending through a side wall of said casing and operatively connectingthe -ring with the expanding device.

.2. In a piston of the character described having a body and anexpansible packing ring mounted in a groove therein, a cylindricalcasing having an external shoulder at one end and threaded part at theother end, an expanding device in said casing, and a thrust memberextending through the wall of said casing and operatively connecting thering with the expanding device.

3. The combination with a piston provided With a perforated groove andan expansible packing ring fitted in said groove of an axially extendingcasing removably mounted in the body portion of the piston, a springdevice in said casing including upper and lower abutment plates, a pairof oppositely bowed leaf springs conned between said plates and havingtheir central portions secured together, said plates having terminalprojections engaging the ends of said spring, a casing plate underlyingthe lower abutment plate and having upwardly extending terminal portionsengaging the ends of said abutment plates, said upwardly extendingterminal portions of the casing plate terminating in inward projectionsoverlying the upper abutment plate, and a thrust member having its innerend engaging the upper abutment plate and its outer end disposed toengage and expand the packing ring.

4. In combination a cylinder having, a front cylinder head presenting aconvex piston opposing portion, a piston operating in said cylinder andhaving an expansible packing ring mounted therein, an axially extendingcasing mounted in the piston, a removable plug carried by the convexportion of the cylinder head and provided With a recess positioned toprovide clearance between the cylinder head and the front end of saidcasing during the forward stroke of the piston, a spring device housedin said casing, and a thrust member extending outwardly from the springdevice and adapted to expand said ring.

5. In a piston of the character described, an expansion unit comprising,a cylindrical casing, laterally expansive means in said casing, saidcasing having a lateral opening adapted to receive a thrust memberengageable with said expansive means, and means for securing said casingin a bore hole.

LOUIS FREEDMAN.

